You should already have a knock alarm or knock gauge....should be a "mandatory" upgrade on any car. I prefer the alarm to the gauge though.
A boost gauge should also be "mandatory", don't rely on the stocker. It's just there for looks. (really)
If you don't have a scan tool you need one of those too.
It's said a stock downpipe is good for low 12's I believe, after that an upgrade should be in order. Unless you want a big one now or are planning to race, I'd keep your stocker for now. Do ensure you have a good exhaust though....meaning no hacked together crap with little bitty ass pipes like mine had. (I made a thread on it..had to redo someone's hack job) Turbo engines like free flowing exhausts.
Also I recommend a turbo tweak chip.
As said the RJC plate just helps keep the front cylinders from leaning out which could set off the knock sensor (which retards timing) or worse blow the headgaskets or even worse blows the engine. A good thing to have. So get one.
Not sure which injectors you have...not sure what they're good for...
The alky move was a good one. That, provided you have good octane, no knock, a good tune, a TT chip will allow you to safely increase boost levels. Do it in little bits at a time and watch for knock. Get ya a Scanmaster, make sure you don't start dropping below 780 with your foot in it, if you do get out of it until you figure out why.
Take a look at my sig at my combo. I managed to bump it up from 14 PSI to 23. Once in awhile I get a false knock but otherwise it's a blast...no track times or dyno numbers yet. Oh, and that's running on 92 octane, the best I can get here.